Tube producing device



March 16, 1965 M. A. BACROlX TUBE PRODUCING DEVICE Filed Jul 11. 1962 3 Sheets-Sheet 1 March 16, 1965 M. A. BACROIX 3,173,595

TUBE PRODUCING DEVICE Filed July 11, 1962 3 Sheets-Sheet 2 Om/enior:

Marcel Andr EA KW X A-H 0 may March 16, 1965 M. A. BACROIX 3,173,595

TUBE PRODUCING DEVICE Filed July 11, 1962 3 Sheets-Sheet 3 DH LnIQI Marcel Andre BA'CRDI X Affomny United States Patent 3,173,595 TUBE PRODUCING DEVICE Marcel Andr Bacroix, Ponta-Monsson, France, assignor to Centre de Recherches de Pont-a-Mousson, Punt-a- Mousson (Meurthe et Moselle), France, a French body corporate Filed July 11, 1962, Ser. No. 209,044 Claims priority, application France, .luly 31, 1961, 869,627 11 Claims. (Cl. 228-) The present invention relates to devices for producing tubes by helically winding a metal band.

Known tube forming devices for producing tubes by a helical winding are of two types.

The first type is represented by the cylindrical corset constituted by a steel tube provided with a longitudinal slot. The sheet metal extends into the interior of the corset through the longitudinal slot and is wound by application thereof against the inner cavity of the corset. Very considerable rubbing of the sheet metal against the corset occurs and high power is consequently required to feed the sheet. Further, the corset is highly heated in the region of the welding station and deteriorates. The corset is opaque and does not allow observing the formation of the tube therein.

The second type employs bending and gauge rollers arranged on a circle so as to impart to the required tube the desired shape and dimensions. It is known to employ outer rollers which envelop the formed coils and inner rollers which are surrounded by said coils.

Owing to the high number of rollers required, difiiculties in the construction, mounting and adjustment, and the high wear of these rollers, this arrangement is a very costly solution.

The object of the invention is to provide an improved device for forming tubes by helically winding a metal band which avoids the aforementioned drawbacks and comprises in combination, a discontinuous series of shoes of low-friction and electrically insulating material which are arranged on a circle so as to form a cylindrical corset corresponding to the outer face of the tube to be obtained, and spraying means for lubricating the contacts between the shoes and the metal band.

Another object of the invention is to provide a machine for continuously producing tubes by helically winding a metal band which is equipped with said forming device.

In this arrangement which is simple, strong and economical, the bending and the feeding of the metal band occur with minimum rubbing.

Further features and advantages of the invention will be apparent from the ensuing description, with reference to the accompanying drawings to which the invention is in no way limited.

In the drawings:

FIG. 1 is a diagrammatic elevational view of a machine equipped with the device according to the invention;

FIG. 2 is an end elevational view with a vertical crosssection taken along line 2-2 of FIG. 1;

FIG. 3 is a sectional view taken along line 3-3 of FIG. 1, and

FIG. 4 is sectional view of a detail of the forming device.

In the embodiment shown in FIGS. 1-4, the invention is shown applied to a machine adapted to continuously helically wind a steel band or strip t and continuously weld the edges of the last coil formed with the adjacent edges of the coil being formed so as to produce a tube T.

The machine comprises a forming device forming the tube T and a feed device feeding the band t.

3,173,595 Patented Mar. 16, 1955 The forming device comprises a stand having a swanneck member 1, a bridge member 2, and on the side corresponding to the member 1 a support block 3 located substantially in the axial plane of the bridge member 2. Two vertical support plates 4 are fixed to the member 1 and the bridge member and to the latter and the support block 3 respectively. The bolsters of the swan-neck member 1 and the bridge member 2 are braced by a horizontal plate 5.

According to the invention, a number of spaced support plates 6 constituting a cradle are fixed to the vertical plates 4 and are supported by the latter in a direction perpendicular thereto and are disposed on an axis XX corresponding to the axis of formation of the tube T. Each of these plates 6 carries shoes 7 composed of an electrically insulating low-friction material, for example plastic or the material known under the trade name Cloron. These shoes have a concave active face 8, are arranged on a circle around the axis XX and their assembly forms a cylindrical corset whose surface corresponds to the outer surface of the tube T to be formed. Each shoe 7 is mounted between two thin plates 9 which are secured to one of the support plates 6 (see FIG. 4).

Combined with this corset is a spraying jet 10 which extends in a direction parallel with the axis XX in front of the first shoes 7 under which the metal band I is engaged. The spraying liquid, which can be water or oil of the machine-tools grade, is supplied to this jet 10 by a pipe 11.

The machine further comprises heating means for locally heating the edges of the band t which are to be welded and consist in the known manner of two electrodes 12 and 13 applied on the adjacent edges a and b (FIG. 3) of the coil being formed and of the last coil S which has already been formed. The two electrodes are connected by conductors 14 and 15 for example to a source of high frequency current (not shown).

The band feed device feeding the band t in a direction which is oblique relative to the axis XX of the formed tube T, comprises a table 16 bordered by parallel slideways 17 in which the edges of the band I slide. Two drive rollers 18 and 19one of which is mounted on top of the band and the other under the band-feed the latter in the direction of the forming device. The upper roller 18 is for example a drive roller driven in rotation by a gear mechanism one of the gears of which is shown at 20.

The machine operates in the following manner:

The metal band t driven by the rollers 18 and 19 is fed thereby to the forming device. The plastic shoes 7 under which this band is engaged constrain the latter to change direction, bend it, and cause it to coil up so as to form the tube T. The spraying liquid sprayed by the jet 10 forms a lubricating film which is interposed between the band and the shoes 7. i

The edge a of the coil s being formed which is adjacent the edge b of the already formed coil S is heated to a white hot welding temperature by the electrode 12 locally in a region of narrow width, whereas the edge b is heated locally to a white hot welding temperature by the electrode 13. Consequently, the adjacent edges of the coil being formed and the already formed coil are welded together when they come into contact with one another. The tube T thus formed issues from the machine on inclined rollers 21.

According to the invention, the band slides easily under the shoes 7 since they are composed of a material having a low coefiicient of friction. They are narrow and therefore in contact with the band over a small area and, moreover, a spraying liquid is employed. Thus, the frictional resistance opposing the helical displacement of the metal the spraying or lubrication, the metal band is neither worn' nor even marked by its passage in the corset, formed :by the shoes 7. i

The shoes 7 must of course be replaced when they have undergone a certain amount of wear, but their wear is small owing to thespraying.

Furthenthe spacing between the plates-6 and the shoes I 7 permit easy access to the welding device welding the edges of the band and avoids. deterioration of th'e'corset by the heating thereof in the, welding region. 7 1

Although a specific embodiment of the invention has been described many modifications and changes may be made therein without departing from the scope ofthe invention as defined inthe appended claims.

Thus the shoes 7 can 'be composed of any insulating low-friction material, such as a synthetic material like I that known under the trade name Teflon or a natural material such as hard wood, for example guaiacum.

The shoes 7 can be disposedobliquely relative to the winding axis XX at the same inclination as the winding helix.

The invention is also applicable to tube-forming machines forming tubes by helically winding a metal band the edges of which band are not welded but clipped together. I

Having now described my invention what I claim as new and desire to secure by Letters Patent isz' 1. In a machine for forming tubes by helically coiling a metal band, comprising a support, a band-coiling die structure fixed on the support and having a longitudinal coiling axis, means for feeding the band at an angle to said axis, the die structure comprising a plurality of fixed axially spaced part-cylindrical concave faces against which the band rubs in the course of formation of the tube, said concave faces having the same radius, ofcurvature and being coaxial on said axis and contained in transverse planes, the die structure being open in the axial spacing between said faces;

2. In a machine for forming 'tubesby helically coiling a 7 axially spaced P r -Cylindrical concave faces against which the band rubs in the course of formation of the tube,said

7 material which is less hard than the metal band and ,to

course of formation of the tube,-the total circumferential extent of said faces in respect of each transverse plane corresponding to the major part of the periphery of the tube and the axial extentofeach face being less than said j axial'spacing between said faces. I I I 1 4. In a machine for formingtubes by helically coiling structure comprising a pluralityof transversely extending axially spaced plates which are rigidly secured tothe support and have apertures which are in coaxial relation to each other on said axis, a plurality of shoes composed of an electrically insulating material having a low coefiicient of friction mounted on each plate on the, periphery of the apertureof the plate and havingpart-cylindrical concave rubbing faces contained in afcylindri'cal plane centered onvv said axis, the rubbing faces being'circum-ferentially spaced apart in said cylindrical plane and the rubbing' fa'ces pertaining to each plate being axially spaced from the rubbing faces of the adjacent plate, and liquid spraying means wardly .onto the die structure and thereby lubricating the rubbing contacts between the coiled band and the rubbing faces in the course of'forma'tion of the tube.

5. A machine as claimed in claim 4, wherein, the rubbing' faces pertaining to each plate are contained in a planeperpendicular to said axis. V t

'6. In a machine for forming tubes by helically coiling a metal band, comprising a support, a band-coiling die structure having a longitudinal coiling axis, means for feeding the band at an' angle relative to said axis, the die structure. comprising a plurality of transversely extending axially spacedplates which are rigidly secured to the entially spaced apart'in'said cylindrical; plane and the concave faces having the-same radius of curvature and being coaxial on said axis and contained in transverse planes, the die structure being open in the axial spacing between said faces and liquid spraying meansIdisposed' above the die structure for spraying liquid downwardly onto the die structure apd thereby' lubricating the rubbing contacts between the band and said, faces in the "courseof formation of i the tube.

3. In a machine for forming tubes by helically coiling a metal band, comprising a support, a band-coiling die structure fixed on the support and having a longitudinal rubbing faces pertaining to each plate being axially spaced from the rubbing faces of the adjacent plate, and liquid spraying means disposed above the die structure for spraying liquid downwardly onto the die structure and thereby lubricating the rubbing contacts between the coiled band and the rubbing faces in the course of'formation of the tube, said means for feeding the band being so located relative to thedie structure that. the band is fed in a plane tangent to a point on the upper part of said cylindrical plane-and the liquid'spraying means isso located relative to the 'diefstr ucture [that the liqu'id'i's sprayed substantially along'a generatrix of said upper part of' said 'cylindri-calplane on the side of said axis remotefrom said ban'd feeding means. a V g 7. A machine as claimedinclairn 6, wherein the shoes are composed of synthetic plastic material.

8 A'machine as claimed in claim 6', wherein the shoes are composed of hard wood.

9. A machine as claimed in claim 6,,wherein two thin .plates fixedon each'side ofeach'shoe and fixed tothe tube, said concave faces having the same radius of cur-' vature and being coaxialzon saida axis and contained in transverse planes, the die structure being open in the axial structure comprising a plurality of transversely extending axially spaced plateswhich; arefrigidlysecureda to the support and havegapertures whichflare in coaxial relation toeach otheron said axis, :aplurality of shoes composed of an' electrically insulating material having a 'low co "efiicientof friction mounted on each plate on the periphery of the aperture of the plate and having part-cylindrical concave rubbing faces contained in a cylindrical plane centered on said axis, the rubbing faces being circumferentially spaced apart in said cylindrical plane and the rubhing faces pertaining to each plate being axially spaced from the rubbing faces of the adjacent plate, a welding device mounted on said support between said axis and the band feeding means for welding the edge of the band fed by the feeding means to the adjoining edge of the band already fed into the die structure, and liquid spraying means disposed above the die structure for spraying liquid downwardly onto the die structure and thereby lubricating the rubbing contacts between the coiled band and the rubbing faces in the course of formation of the tube, said means for feeding the band being so located relative to the die structure that the band is fed in a plane tangent to a point on the upper part of said cylindrical plate and the liquid spraying means is so located relative to the die structure that the liquid is sprayed substantially along a generatrix of said upper part of said cylindrical plane on the side of said axis remote from said band feeding means.

11. In a machine for forming tubes by helically coiling a metal band, comprising a support, a band-coiling die structure having a longitudinal coiling axis, means for feeding the band at an angle relative to said axis, the die structure comprising a plurality of transversely extending axially spaced plates which are rigidly secured to the support and have apertures which are in coaxial relation to each other on said axis, a plurality of shoes composed of an electric insulating material having a 10W coefficient of friction mounted on each plate on the periphery of the aperture of the plate and having part-cylindrical concave rubbing faces contained in .a cylindrical plane centered on said axis, the rubbing faces being circumferentially elongated and circumferentially spaced apart in said cylindrical plane a distance less than the circumferential extent of each rubbing face, the rubbing faces of each plate being axially spaced apart from the rubbing faces of the adjacent plate a distance greater than the axial extent of the rubbing faces, and liquid spraying means disposed above the die structure for spraying liquid downwardly onto the die structure and thereby lubricating the rubbing contacts between the coiled band and the rubbing faces in the course of formation of the tube, said means for feeding the band being so located relative to the die structure that the band is fed in a plane tangent to a point on the upper part of said cylindrical plane and the liquid spraying means is so located relative to the die structure that the liquid is sprayed substantially along a generatrix of said upper part of said cylindrical plane on the side of said axis remote from said band feeding means.

References Cited by the Examiner UNITED STATES PATENTS CHARLES W. LANHAM, Primary Examiner, 

1. IN A MACHINE FOR FORMING TUBES BY HELICALLY COILING A METAL BAND, COMPRISING A SUPPORT, A BAND-COILING DIE STRUCTURE FIXED ON THE SUPPORT AND HAVING A LONGITUDINAL COILING AXIS, MEANS FOR FEEDING THE BAND AT AN ANGLE TO SAID AXIS, THE DIE STRUCTURE COMPRISING A PLURALITY OF FIXED AXIALLY SPACED PART-CYLINDRICAL CONCAVE FACES AGAINST WHICH THE BAND RUBS IN THE COURSE OF FORMATION OF THE TUBE, SAID CONCAVE FACES HAVING THE SAME RADIUS OF CURVATURE AND BEING COAXIAL ON SAID AXIS AND CONTAINED IN TRANSVERSE PLANES, THE DIE STRUCTURE BEING OPEN IN THE AXIAL SPACING BETWEEN SAID FACES. 